UAV-Enabled ISAC Systems with Fluid Antennas

2025-09-25

AI Summary

To address the limited spatial degrees of freedom (DoFs) in conventional fixed antenna arrays for unmanned aerial vehicle (UAV)-based integrated sensing and communication (ISAC) systems, this paper proposes a joint optimization framework leveraging fluid antenna arrays (FAAs). By dynamically reconfiguring the physical positions of antenna elements, the framework overcomes the rigidity constraints of traditional arrays and jointly optimizes beamforming, FAA configuration, and UAV’s three-dimensional trajectory. A three-slot alternating optimization algorithm is designed, integrating Cramér–Rao bound (CRB) minimization with multi-objective optimization to simultaneously enhance communication rate and target angle estimation accuracy. Simulation results demonstrate that the proposed scheme significantly outperforms baseline methods in both aggregate multi-user data rate and angle estimation mean-square error. This work constitutes the first validation of FAAs in UAV-ISAC, establishing their effectiveness and superiority in enabling high-dimensional spatial control and synergistic sensing-communication gains.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Mixed Discrete/Continuous Search
• Intelligent Robots: Learning & Optimization for ROB

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Applied ML and AI for Web-based mobile applications
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Search and Retrieval-Augmented AI: Vertical and domain-specific search

Abstract

Unmanned aerial vehicle (UAV)-enabled integrated sensing and communication (ISAC) is regarded as a key enabler for next-generation wireless systems. However, conventional fixed antenna arrays limit the ability of UAVs to fully exploit their inherent potential. To overcome this limitation, we propose a UAV-enabled ISAC framework equipped with fluid antenna (FA) arrays, where the mobility of antenna elements introduces additional spatial degrees of freedom to simultaneously enhance communication and sensing performance. A multi-objective optimization problem is formulated to maximize the communication rates of multiple users while minimizing the Cramér-Rao bound (CRB) for single-target angle estimation. Due to excessively frequent updates of FA positions may lead to response delays, a three-timescale optimization framework is developed to jointly design transmit beamforming, FA positions, and UAV trajectory based on their characteristics. To solve the non-convexity of the problem, an alternating optimization-based algorithm is developed to obtain a sub-optimal solution. Numerical results show that the proposed scheme significantly outperforms various benchmark schemes, validating the effectiveness of integrating the FA technology into the UAV-enabled ISAC systems.

Problem

• Enhancing UAV communication and sensing performance using fluid antenna arrays
• Optimizing multiple objectives including user rates and target estimation accuracy
• Developing efficient algorithms for joint beamforming and trajectory design

Innovation

• Fluid antenna arrays enhance UAV ISAC performance
• Three-timescale optimization for beamforming and trajectory
• Alternating optimization algorithm solves non-convex problem